refactor: Allow latest Ansible version
refactor: Allow latest Ansible version

The Ansible version was locked down in the install script due to a bug
in version 2.2.0.0 (commit cab61b7).

This bug has been fixed in a subsequent Ansible release.

Change-Id: If849166f191cbd48b4b05074c22877a0a30fda7a

open-power-ref-design-toolkit/cluster-genesis,open-power-ref-design-toolkit/cluster-genesis